Static and interference eliminator for radio apparatus



March 6, 1-934. M DER 1,949,440

STATIC AND INTERFERENCE ELIMINATOR FOR RADIO APPARATUS Filed Aug. 2. 1929 Inventor JM. VV Z'Ider B fm Attorneys Patented Mar. 6, 1934 UNITED STATES PATENT OFFICE STATIC AND INTERFERENCE ELIMINATOR FOR RADIO APPARATUS 1 Claim.

My invention relates to novel means for the practical elimination of foreign noises, caused by static and interference, from the transmission and reception of radio signals modulated with 5 audio currents.

In its essence my invention contemplates transmission on multiple carrier waves of identical audio modulation but differing in phase or polarity, and reception of such multiple carrier waves by multiple receiving circuits so connected and arranged as that each will give an identical response in its electrical output that controls the sound reproduction, whereas the electrical output of each receiving circuit derived from signals not difiering in phase or polarity will be such as to counteract each other thereby failing to be impressed on the reproduction mechanism. Thus, the multiple receiving circuits in response to multiple carrier waves of reverse polarity can be designed to give responses of like polarity which acting jointly will energize or control the energization of the loud speaker, but in response to static signals which are impressed in like wave form and polarity on all receiving circuits, their responses would be of reverse polarity and would thus neutralize each other and be Without any efiect on the loud speaker.

My invention contemplates associating a signal reproducing mechanism of whatsoever character with means, mechanical or otherwise, that will respond only to a plurality of simultaneous impulses derived from signals of dissimilar carrier Waves.

Preferably, means, responsive only to correspending and synchronous movements of a actuators controlled by said receiving circuits, will actuate the signal reproducing mechanism, or an electrical regenerator of the original modulations from the transmitting station for reproducing electrically the original audio waves for further amplification before being impressed upon the sound reproducing mechanism.

Where mechanical means are controlled by the actuators, they are designed to block any differential or non-synchronous movements of the actuators, thereby efiectively killing all spurious signals and confining the sound output to the control solely of the multiple carrier waves of predetermined characteristics from the selected transmission station.

In the accompanying drawing I have illustrated one means for carrying my invention into effect, but it is to be understood that such means are susceptible of wide variation within the scope 56 of my invention.

Fig. 1 illustrates diagrammatically multiple carrier wave transmitting and receiving mechanisms with a mechanical means for reproducing the selected signal output in suitable form for electrical amplification.

Fig. 2 illustrates the mechanical reproducer as directly connected to the sound reproducing diaphragm of a loudspeaker, in connection with an alternate arrangement whereby the reversal of like impulses is efiected mechanically.

Like reference numerals refer to like parts throughout.

In the embodiment of my invention illustrated in Fig. l, 5, is a source of electrical signals to be transmitted; 6, illustrates a transformer or coupling device giving two current outputs of identical audio character but differing in polarity or phase. The independent carrier waves produced by the transmitting sets 7 and 8 differ in frequency or wave length but are modulated by the same signal with, however, the prescribed difference in polarity or phase.

I indicate standard receiving sets at 9 and 10 in which it will be noted the polarity of the aerial and ground of each in respect to the audio modulation of the carrier waves are reversed for the prescribed signal impulse. The connections 11 are reversed between the set 9 and its respective solenoid 12 shown as a conventional illustration of a magnetic actuator :for converting electrical impulses impressed thereon into mechanical motion.

The set 10 is connected by non-reversed circuits 13 to its respective solenoid 12. Each solenoid l2 actuates a reciprocable plunger 14 confined to rectilinear motion by guides 15. Each plunger carries a driving slide 16 and each slide 16 works in an inclined guide 21 on a reciprocable slide 17 confined by guides 18 to rectilinear motion at right angles to the plunger motion. The guides 21 are inclined similarly at an acute angle to the plunger motion, and the slide controls an electrical means, as shown at 19, Fig. 1, for translating mechanical movements into electrical signals to be amplified in any suitable way.

In Fig. 2 the reversal of the efiect of the impulses received over the receiving circuits is accomplished mechanically, the sets 9 and 10 here having identical circuit connections 13 to the solenoids 12. The reversal is obtained by permitting the plungers to move oppositely, as they would tend to do responsive to the selected signal impulse, the guides 21 being reversed in angular relationship so that opposed plunger movements co-act to reciprocate the slide. Here the slide 22 is shortened and the slides 21 brought together so that angular thrust thereon is reduced to a minimum. Here I show the slide 22 connected to the diaphragm 23 of a loud speaker to directly operate it.

In operation, assuming the differentiation in the signals on the multiple carrier waves is in respect of their polarity, the receiving sets 9 and 10 will receive corresponding signals of reverse polarity, which signals, due to the reversal of the circuit 11, will impress the solenoids 12 in identical manner and the like resulting plunger movements will co-act to reciprocate the slide 17, or, where the circuits 11 and 13 are not reversed, the opposed plunger movements will co-act, as shown in Fig. 2, to reciprocate the slide.

If the signals received by the sets are of like polarity the resulting plunger movements would be opposed, did the slide permit same, but obviously the rigid slide will block any plunger movements that do not act synchronously and correspondingly thereon, causing them to balance each other and therefore leaving the slide fully sensitive to any unbalanced plunger impulses.

The mechanical means to balance out the opposed circuit output impulses is simplest to describe and easiest to illustrate, but obviously my invention contemplates the employment of any means, electrical or mechanical, to accomplish the same end, i. e., to nullify non-complementary impulses from the receiving set and to respond fully and freely to complementary impulses derived from the differentiated signals received from the selected transmitting station.

The two independent transmitting equipments may be built into a joint and common housing, or on associated panels as one complete double carrier transmitting set, each of which is modulated by the signal to be sent in identical fashion except that the phase condition is different in one with respect to the other. In the simplest type the phase angle relationship is 180 giving absolute reversal of polarity.

The two receiving circuits may be built into one complete set with a common housing and a common amplifying or sound reproducing means for signal impulses that have actuated the translating means. Obviously, a signal impulse received over only one of the receiving circuits will be ineffective to actuate the slide 17 and reproduce itself because the friction angle or the guide 21 for the wave actuated plunger is such as to hold slide 17 against movement. In other words, the translating means is non-reversible responsive to signal impulses from either receiving circuit alone as Well as to non-identical nonsynchronous signal impulses over both receiving circuits.

Though I have described with great particularity the details of the embodiment of the invention herein shown, it is not to be construed that I am limited thereto, as changes in arrangement and substitution. of equivalents may be made by those skilled in the art without departing from the invention as defined in the appended claim.

What I claim is:

In a receiving equipment for receiving multiple radio signals, a plurality of electro-mechanical actuators each of which is responsive to its respective de-modulated audio signal, and a sound reproduction means controlled by a coordinated synchronized operation of said actuators.

JOHN M. WILDER. 

